Classifications

• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61C—DENTISTRY; APPARATUS OR METHODS FOR ORAL OR DENTAL HYGIENE
  • A61C8/00—Means to be fixed to the jaw-bone for consolidating natural teeth or for fixing dental prostheses thereon; Dental implants; Implanting tools
  • A61C8/0012—Means to be fixed to the jaw-bone for consolidating natural teeth or for fixing dental prostheses thereon; Dental implants; Implanting tools characterised by the material or composition, e.g. ceramics, surface layer, metal alloy
  • A61C8/0013—Means to be fixed to the jaw-bone for consolidating natural teeth or for fixing dental prostheses thereon; Dental implants; Implanting tools characterised by the material or composition, e.g. ceramics, surface layer, metal alloy with a surface layer, coating
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
  • A61F2/00—Filters implantable into blood vessels; Prostheses, i.e. artificial substitutes or replacements for parts of the body; Appliances for connecting them with the body; Devices providing patency to, or preventing collapsing of, tubular structures of the body, e.g. stents
  • A61F2/02—Prostheses implantable into the body
  • A61F2/30—Joints
  • A61F2/30767—Special external or bone-contacting surface, e.g. coating for improving bone ingrowth
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61L—METHODS OR APPARATUS FOR STERILISING MATERIALS OR OBJECTS IN GENERAL; DISINFECTION, STERILISATION OR DEODORISATION OF AIR; CHEMICAL ASPECTS OF BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES; MATERIALS FOR BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES
  • A61L27/00—Materials for grafts or prostheses or for coating grafts or prostheses
  • A61L27/28—Materials for coating prostheses
  • A61L27/30—Inorganic materials
  • A61L27/306—Other specific inorganic materials not covered by A61L27/303 - A61L27/32
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61C—DENTISTRY; APPARATUS OR METHODS FOR ORAL OR DENTAL HYGIENE
  • A61C8/00—Means to be fixed to the jaw-bone for consolidating natural teeth or for fixing dental prostheses thereon; Dental implants; Implanting tools
  • A61C8/0012—Means to be fixed to the jaw-bone for consolidating natural teeth or for fixing dental prostheses thereon; Dental implants; Implanting tools characterised by the material or composition, e.g. ceramics, surface layer, metal alloy
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
  • A61F2/00—Filters implantable into blood vessels; Prostheses, i.e. artificial substitutes or replacements for parts of the body; Appliances for connecting them with the body; Devices providing patency to, or preventing collapsing of, tubular structures of the body, e.g. stents
  • A61F2/02—Prostheses implantable into the body
  • A61F2/30—Joints
  • A61F2/3094—Designing or manufacturing processes
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
  • A61F2/00—Filters implantable into blood vessels; Prostheses, i.e. artificial substitutes or replacements for parts of the body; Appliances for connecting them with the body; Devices providing patency to, or preventing collapsing of, tubular structures of the body, e.g. stents
  • A61F2/02—Prostheses implantable into the body
  • A61F2/30—Joints
  • A61F2/30767—Special external or bone-contacting surface, e.g. coating for improving bone ingrowth
  • A61F2002/30906—Special external or bone-contacting surface, e.g. coating for improving bone ingrowth shot- sand- or grit-blasted
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
  • A61F2310/00—Prostheses classified in A61F2/28 or A61F2/30 - A61F2/44 being constructed from or coated with a particular material
  • A61F2310/00005—The prosthesis being constructed from a particular material
  • A61F2310/00011—Metals or alloys
  • A61F2310/00023—Titanium or titanium-based alloys, e.g. Ti-Ni alloys
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
  • A61F2310/00—Prostheses classified in A61F2/28 or A61F2/30 - A61F2/44 being constructed from or coated with a particular material
  • A61F2310/00005—The prosthesis being constructed from a particular material
  • A61F2310/00011—Metals or alloys
  • A61F2310/00035—Other metals or alloys
  • A61F2310/00089—Zirconium or Zr-based alloys
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
  • A61F2310/00—Prostheses classified in A61F2/28 or A61F2/30 - A61F2/44 being constructed from or coated with a particular material
  • A61F2310/00005—The prosthesis being constructed from a particular material
  • A61F2310/00011—Metals or alloys
  • A61F2310/00035—Other metals or alloys
  • A61F2310/00125—Hafnium or Hf-based alloys
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
  • A61F2310/00—Prostheses classified in A61F2/28 or A61F2/30 - A61F2/44 being constructed from or coated with a particular material
  • A61F2310/00005—The prosthesis being constructed from a particular material
  • A61F2310/00011—Metals or alloys
  • A61F2310/00035—Other metals or alloys
  • A61F2310/00131—Tantalum or Ta-based alloys
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
  • A61F2310/00—Prostheses classified in A61F2/28 or A61F2/30 - A61F2/44 being constructed from or coated with a particular material
  • A61F2310/00389—The prosthesis being coated or covered with a particular material
  • A61F2310/00592—Coating or prosthesis-covering structure made of ceramics or of ceramic-like compounds
  • A61F2310/00802—Coating or prosthesis-covering structure made of compounds based on metal hydrides
  • A61F2310/00808—Coating made of titanium hydride
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T428/00—Stock material or miscellaneous articles
  • Y10T428/25—Web or sheet containing structurally defined element or component and including a second component containing structurally defined particles
  • Y10T428/254—Polymeric or resinous material

Definitions

• the present invention relates to a biocompatible implant consisting essentially of a metal such as titanium, zirconium, hafnium and tantalum, or an alloy thereof, the surface of which has been modified m order to increase the biocompatibility .
• the invention also relates to a method modification of surfaces to.
• Titanium, zirconium, hafnium and tantalum and their alloys have a superb corrosion resistance m body fluids and are well accepted by the human body. Titanium and its alloys are therefore much used for implants. In many applications it is of utmost importance that the metal form a strong and lasting connection with the surrounding tissues and that this connection does not impair healing. This is not easy to achieve. Implant materials not giving satisfactory healing usually lead to loss of contact between the implant and tissue, often followed by complica- tions leading to implant failure. This has given the patients severe pain and required costly medical treatment often including complicated and expensive surgery.
• EP-A- 0 264 354 describes a process for forming a coating of a calcium phosphate compound on the surface of the titanium oxide layer. In the process to obtain the desired oxide layer it is possible to use either acid treatment or formation of an intermediate metal hydride, which is then heated m order to obtain the desired oxide as a substrate for the calcium phosphate coating.
• Another method for treating the surface of endosse- ous implants is to use the process described m EP-
• A-0 212 929 according to which a ceramic material is thermally sprayed onto the metal surface after its been roughened with an appropriate technique .
• the roughening of the metal surface may be obtained by e.g. thermally spraying titanium hydride onto it, but, as for EP-A-
• the titanium hydride coated implant is only an intermediate product in the process of obtaining the desired end product, m this case the ceramic coated implant .
• Summary of the invention The object of the present invention is to provide an implant with improved biocompatibility compared to known implants. This is obtained by modifying the surface of the implant. The modified surface further promotes contact between tissue ant implant.
• implants coated with titanium hydride led to a better adherence between the metal and bone, compared to other titanium implants.
• the fact that titanium hydride coated implants could be used directly is very surprising; up to the present invention it has been considered necessary to coat hydrided surfaces to achieve satisfactory biocompatibility.
• In the work leading to the present invention it was demonstrated in animal models that tissues in contact with the titanium hydrided titanium surface was healthy and showed no foreign body reactions as examined by microscopy.
• the present invention thus relates to biocompatible metallic implants, characterized in that the surfaces of the implants have been modified so that they comprise a metal hydride layer.
• the invention also relates to a method for the production of a biocompatible implant, wherein a core of metal or an alloy thereof is coated with a surface layer of hydride .
• the invention relates to a biocompatible implant consisting essentially of metal or an alloy thereof, characterized in that the surface of the im- plant is modified, preferably so that it comprises an outer layer, preferably essentially consisting of a metal hydride.
• biocompatible implant used herein relates to implants suitable for introduction into the body of a mammal, and especially of a human.
• the implants according to the invention or implants produced with the method according to the invention are intended for introduction into all living hard and soft tissues, including bone, cartilage and teeth, and all body cavities including joints and inner ear.
• the hydride layer in the implant according to the invention may be any metal hydride or a mixture of sev- eral different metal hydrides.
• the major part of the modified outer layer i.e. more than 50%, is preferably constituted by TiH ⁇ . 924 or TiH 2 .
• This titanium hydride layer may also comprise small amounts of other elements and hydrides thereof.
• the invention also relates to a method suitable for the production of the above described biological implant.
• This method results in an implant surface, which comprises a layer of hydride.
• This may be performed either by coating with a layer of hydride, or by converting the surface into hydride. It is possible to use a commercially available implant and convert its surface to comprise a hydrided layer. It is also possible to produce the implant according to the invention, by first produc- ing a suitably shaped core of titanium or an alloy thereof, and then accomplish the titanium hydride layer.
• the method according to the invention is preferably performed by treating the starting implant or core by electrolysis. The starting implant is then placed in an electrolytic bath. During the electrolysis, the starting implant will constitute the cathode.
• the electrolytic bath is preferably an aqueous solution of NaCl with acidic pH-value.
• the pH is preferably adjusted to the appropriate value by addition of HCl , H 2 S0 , HN0 3 , HCIO 4 , or an organic acid or a mixture of two or more of these acids.
• the temperature of the electrolytic bath should also be adjusted. It is possible to perform the method according to the invention at ambient temperature, i.e. at approximately 20°C, however, at this temperature the reac- tion rate will be very slow. In order to increase the reaction rate, the temperature should be raised, preferably to at least 40°C, and most preferably to at least 80°C.
• the most preferred electrolytic solution for use in the method according to the invention is an aqueous solu- tion comprising from 0,01 M to 1 M of a saturated salt solution and from 10 "5 to 10 M of at least on of the above mentioned acids.
• the current used to perform the electrolysis is 0.001 - 1000 mA/cm 2 .
• Fig. 1 illustrates the thickness of titanium hydride layers obtained by electrolysis of titanium implants at different temperatures and pH-values (see Example 1) ; and Fig. 2 illustrates the forces necessary to pull out implants according to the invention compared to control implants, from the tibia of rabbits (see Ex- ample 4) .
• Titanium Grade 2 Specimens of Titanium Grade 2 were carefully cleaned by ultrasonic treatment with t ⁇ chlorethylene for 15 mm, rinsed in ethanol, and then ultrasonic treated with etha- nol for 10 mm. This was repeated three times, and the specimens were then rinsed in water. The clean specimens were then cathodically polarized m a bath consisting of 0.5 M NaCl and 1 M HCl . The presence of a titanium hydride after the electrolysis was confirmed by X-ray dif- fraction analysis.
• the electrolysis was performed at different temperatures, 25°C and 80°C, in order to study the influence of the temperature on the obtained titanium hydride layer, and also at different pH-values, pH 0 and pH 2 , in order to study the influence of the pH.
• the thickness of the obtained titanium hydride layer was determined by microscopy of metallographic cross sections.
• the thickness as a function of the time used for the treatment is shown in figure 1. As evident from the figure, it is preferable to use a temperature of 80°C compared to a temperature of 25°C.
• implants were made of tita- mum grade 2.
• the implants were threaded and had a diameter of 3.5 mm and a length of 4.5 mm.
• the implants were made to fit the bones of rabbits.
• the implants were treated for 18 hours the same bath and under the same conditions as used in example 1. After sterilization by autoclavmg, these implants (Implants of the invention) were introduced by surgery in the femurs of four rabbits. These rabbits were reproduced with special care to render animals with very similar genetics.
• implants that were only cleaned and autoclaved were introduced in similar positions the rabbits.
• the rabbits were euthanized after 8 weeks.
• the adherence between the implants and the bone was recorded for eight implants with titanium hydride coating and four implants that had only been cleaned and autoclaved.
• the adherence was determined by measuring the torque force (Ncm) needed to loosen the implants from the femur of the rabbits. The results are shown in table 1 below.
• Example 3 Strength and stability of interface between metal and bone is critical to the long-term performance of load bearing implants in particular bone with poor quality. Data has been presented that rough surfaces induce better bone response, however the ideal type and degree of roughness remains unknown.
• the implants had the shape of disks, and they were machined from a 10 mm round bar of grad 2 titanium (ASTM B 348) .
• the size of the disks was 6,25 ⁇ 0,01 mm in diameter with a thickness of 2.0 + 0,05 mm.
• All disks were standardised with grinding disc from #800 to #1200 grit size and polished with 6 ⁇ diamond abrasive, according to Struers ® Metalog Guide before fur- ther treatments.
• All disks were pre-treated with trichloroethylene in an ultrasonic bath for 30 min, rinsed with ethanol then ethanol in ultrasonic bath for 3x10 -min, and finally rinsed with deionized water.
• a total of forty-eight implants were divided into three groups: Group 1: implants with electropolished surfaces, Group 2: implants that were blasted with Ti0 2 particles with a grain size of 22-28 ⁇ m, and Group 3: implants that were blasted with Ti0 2 particles with a grain size of 180-220 ⁇ m. Eight implants in each group were used as controls, while the other eight in each group were treated according to the invention. Four implants, one from each group were randomly in-operated into the tibial bone of each of the twelve New Zealand White rabbits.
• the rabbits were given Fentanyl/fluanison (Hypnorm®) 0,05-0,1 ml/kg s.c. 10 minutes prior to being removed from their cages.
• the operation sites were depilated and washed with soap and ethanol prior to a sterile cover of the lover part of the rabbit .
• the rab- bits were anaesthetised with Midazolam (Dormicum®) 2mg/kg bw i.v. If the animals started to show signs of waking up between 0,1 to 0,5 diluted Hypnorm® (1 ml Hypnorm® and 9 ml sterile water) was injected i.v. slowly until an adequate effect was obtained.
• Lidocain (Xylocain/adrenaline®) 1,8 ml s.p. in joint site, tuber- ositas tibiae, was used.
• the animals were placed p «fe on the operation table on their back, covered with sterile cloths prior to disinfection with 70 % etanol . Their eyes were protected for drying with ointment.
• the fixation of the implants to bone was then evaluated using a pull-out test.
• the rabbits were sacrificed with an over-dose i.v. and an mtracardiac injection with Pen- tobarbital (Mebumal®) while under sedation with Hyp- norm® .
• the equipment used to apply pull-out force was Lloyds LRX Materials Testing machine.
• the ball -attachment on the metal pin was fit in a holder connected to a load cell of 500 N. This attachment was designed to avoid any shear and tilt forces on the implant and tolerates for the axis of the implant not being precisely perpendicular on the bone surface.
• Crosshead speed range was set to 1,0 mm/min. Force measuring accuracy was set to +/- 1%.

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• 1998
  • 1998-12-23 SE SE9804536A patent/SE9804536D0/xx unknown
• 1999
  • 1999-12-22 AU AU30685/00A patent/AU764293B2/en not_active Ceased
  • 1999-12-22 NZ NZ513080A patent/NZ513080A/en not_active IP Right Cessation
  • 1999-12-22 CA CA2356916A patent/CA2356916C/en not_active Expired - Fee Related
  • 1999-12-22 EP EP99964764A patent/EP1150724B1/en not_active Expired - Lifetime
  • 1999-12-22 DE DE69926915T patent/DE69926915T2/de not_active Expired - Lifetime
  • 1999-12-22 US US09/868,965 patent/US6627321B1/en not_active Expired - Lifetime
  • 1999-12-22 AT AT99964764T patent/ATE302620T1/de not_active IP Right Cessation
  • 1999-12-22 WO PCT/IB1999/002093 patent/WO2000038753A1/en active IP Right Grant
  • 1999-12-22 ES ES99964764T patent/ES2247852T3/es not_active Expired - Lifetime
  • 1999-12-22 JP JP2000590704A patent/JP4719841B2/ja not_active Expired - Lifetime
• 2001
  • 2001-06-22 NO NO20013131A patent/NO321694B1/no not_active IP Right Cessation

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